The forested slopes of Sheshan Hill rise a hundred meters above the plains of once rural, now suburban, Songjiang District in the southwest corner of sprawling Shanghai. At the top, China’s only Catholic basilica – an eighty-year old red brick building with an onion dome – is flanked on one side by the white dome of a modern telescope, and on the other by the century-old buildings that constitute the Shanghai Astronomical Observatory. Most mornings, the hilltop is silent but for a handful of priests and a few locals willing to climb the old stone stairways to go to mass. But this morning was a bit different: Sheshan was in the path of the century’s longest eclipse, and the local media had recommended it as one of three ideal locations for watching the event.

By 7 AM, tour buses were rumbling up the narrow cobblestone road that winds around the mountain. The site is a prime viewing spot, overlooking several miles of former rice fields, now turned to golf courses and the high-end residential compounds favored by the Party aristocracy. Yet despite the tour buses, media recommendations, and groups from as far away as Hong Kong, by 8 AM it was clear that the gathering was going to fall far short of the 5,000 visitors the government had anticipated. Weather, no doubt, was the culprit: local meteorologists had been warning for days that clouds and thunderstorms were likely to eclipse the eclipse.

Beijing’s superstitious State Council – the same people who scheduled the Olympics for 8-8-08 at 8:08 – might have preferred that no one take note of the event. In China, eclipses are traditionally harbingers of disaster and dynastic change. Over the weekend, the Council had issued a directive encouraging government science agencies to teach only the scientific meaning behind the eclipse, and to eliminate any superstitious discussion. As Shanghai’s 94-year old bishop recently told me, in the old days “the emperor, his priests, the whole court, they’d fast – fast until [an eclipse] was over.”

Despite the rain clouds and ominous portents, roughly a hundred tourists crowded atop a balcony that wraps around one of the Observatory’s old telescopes. With their backs to the basilica, they turned toward the East, and a rising sun which, at 8:30 AM, broke through the clouds to reveal the moon’s disc just beginning to cross the sun’s. Most in the crowd rushed to put on the disposable eye-protecting “eclipse glasses” of the sort that had been on sale in Shanghai for weeks.

Minutes later, the clouds crossed the sun for the last time and downpour began to drench tourists, cameras, and telescopes. Most of the crowd ran for shelter in the old Observatory building. I joined a smaller group who rushed down a steep, slick stairway into a narrow cobblestone lane that winds between two- and three-story buildings constructed during the early decades of the last century. Few noticed the slight, studious figure of C.J. Yang, a retired theoretical physicist who spent most of his career with NASA’s Goddard Space Flight Center. Standing in front of a pair of ancient wooden double doors, he shook his head and clucked his tongue. “A pity that they won’t be able to see anything.” We’d met earlier, while I was scouting for an appropriate viewing location, and he beckoned me now into an impromptu lab where he was in the midst of an eclipse-related experiment.

Inside, Dimitrie Olenici of the Suceava Planetarium in Suceava, Romania was crouched beside a swinging brass pendulum that he’d suspended from the ceiling. “So many millions of people in Shanghai cannot see the eclipse,” he declared to me from beneath his wide-brimmed straw hat. “But I can see the eclipse. I can see it using my pendulum!” At the invitation of Yang and the Shanghai Astronomical Observatory, he was busy investigating the so-called Allais Effect. Named for a Nobel Prize winning economist, the controversial phenomenon posits that during an eclipse the moon temporarily shields the Earth from the sun’s gravity – an effect most easily observed by measuring the oscillations in a swinging pendulum. Decades of data indicates that something does in fact happen to a pendulum during an eclipse, but few scientists are willing to ascribe the effect to gravity. Doing so, Professor Yang points out, would challenge established theories about how gravity really works – including, potentially, some of Einstein’s theories. “So we are outside of the mainstream,” he says. “But that’s the only way to push forward physics from its current rut.”

“See!” Professor Olenici called out. “There is the shock.” He lifted a piece of graph paper upon which he had just plotted a chart showing what he said was the moon’s interference with the local gravity. Professor Yang rushed over to see. He plans to use the data to determine “the speed of gravity.” At his recommendation, I took leave to experience the total darkness of the eclipse, rain or no rain.

“Eclipse totality” – that is, the moment of total darkness when the moon’s disc obscures the sun’s – occurred at exactly 9:36 AM. The cobblestone lanes of the Observatory rushed with water and the bright reflections of electric lights coming from doorways and open windows were silhouetted with figures staring up into the wet, black morning. I climbed a stairway leading up to the Observatory’s portico, and found a group of perhaps fifty people, some with umbrellas, some without, all angled toward where the sun had been – now hidden behind sheets of rain, clouds, and the moon. A handful of young Europeans began to dance wildly, as if at an impromptu rave. Nearby, several Chinese illuminated the darkness with flash photos pointed at the sky. Below, in the parking lot veranda, perhaps two-hundred observers stared out into a darkness cut only by the taillights of a tour bus that was idling for the benefit of a rain-drenched group of Japanese.

Then, almost instantly, the sky turned gray. To my eyes, and those of several people around me, it was as though someone had flipped a light-switch. All around, cell phones began to ring and voices talked excitedly about what had just transpired. I answered mine and spoke to a friend in Shanghai who complained, vociferously, that the government had turned on the downtown streetlights, thus spoiling the eclipse for everyone. She said she should have come to Sheshan.